fordy136, shut up you wally. stick ya head under the bonnet an shut it.
sounds like you have a flow valve faulty.
what yr is it ?
sonray heating., June 2008
hmmm i'd like to witness that problem for myself, micra's are 'sound' cars but you've added a mod. if there was a problem with the thermostat then it would stay hot... but yours aint doing that. did you bleed the system when you fitted it?? look at all the radiator pipes and find the highest point.. you should then find a bleed nipple. run the car and undo the bleed nipple and be ready to tighten it up! where protective equipment because it could get hot! be careful and gd luck!
HOPE IT HELPS!
ben